This invention relates generally to vascular access devices and methods, including catheter assemblies and devices used with catheter assemblies. Generally, vascular access devices are used for communicating fluid with the vascular system of patients. For example, catheters are used for infusing fluid, such as normal saline solution, various medicaments, and total parenteral nutrition, into a patient, withdrawing blood from a patient, or monitoring various parameters of the patient's vascular system.
A common type of intravenous (IV) catheter is an over-the-needle peripheral IV catheter. As its name implies, an over-the-needle catheter is mounted over an introducer needle having a sharp distal tip. At least the inner surface of the distal portion of the catheter tightly engages the outer surface of the needle to prevent peelback of the catheter and thus facilitate insertion of the catheter into the blood vessel. The catheter and the introducer needle are assembled so that the distal tip of the introducer needle extends beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient's skin. The catheter and introducer needle are generally inserted at a shallow angle through the patient's skin into a blood vessel.
In order to verify proper placement of the needle and/or catheter in the blood vessel, the clinician generally confirms that there is “flashback”, or flow, of blood into a flashback chamber of the catheter assembly. Once proper placement of the catheter into the blood vessel is confirmed, the clinician may apply pressure to the blood vessel by pressing down on the patient's skin over the blood vessel distal of the introducer needle and the catheter. This finger pressure occludes the vessel, minimizing further blood flow through the introducer needle and the catheter.
The clinician may then withdraw the introducer needle from the catheter. The introducer needle may be withdrawn into a needle shield device that covers the needle tip and prevents accidental needle sticks. In general, a needle shield includes a housing, a sleeve, or other similar device that is designed such that when the needle is withdrawn from the patient, the needle tip will be trapped/captured within the needle shield. The purpose of these needle shield devices is to house the tip of the needle in a secure location, thereby avoiding the possibility of needle sticks.
The needle and needle shield device, if used with the needle, are then separated from the catheter, which is left in place to provide intravenous access to the patient. Other vascular access devices may then access the catheter in order to continue patient treatment. During the entire period of catheter use, systems and methods are needed to continuously verify and maintain the proper vascular access device position within the vasculature of a patient.